Challenge of the Unknown
| First published | October 1973 |
|---|---|
| Type | Short Fiction |
| Length | Novella |
| Date | Publication | Publisher | Type | Page | |
|---|---|---|---|---|---|
| October 1973 |
|
Perry Rhodan #32: Challenge of the Unknown | Ace Books | MAGAZINE | 11 |
| 1978 |
|
Challenge of the Unknown | Orbit | Chapbook |